In accordance with Request for Applications (RFA) MH-92-03, this proposal details plans for subject recruitment, subject selection, stimulant medication assessments, and long-term psychosocial treatment procedures relevant to a multisite/multimodal treatment study for children with attention-deficit hyperactivity disorder (ADHD). The clear risks to health, social relationships, academic success, and prognosis that are incurred by children with ADHD mandates close examination of combinations of efficacious intervention modalities. Indeed, the need for well-controlled, multimodality treatment research is underscored by the lack of sufficiency of single intervention modalities, including stimulant medication and behavior modification procedures, the two best-researched treatments for the disorder. This proposal thus provides information relevant to (a) broad-based subject recruitment procedures, designed to obtain wide ethnic diversity and to include substantial numbers of girls with ADHD; (b) multiple-gating assessment procedures, which will yield a final sample of 8-10 year-old children who meet stringent inclusionary and exclusionary criteria for ADHD and who represent the range of comorbid diagnoses that pertain to ADHD; (c) within-subject trials of stimulant medications--both methylphenidate and dextroamphetamine--to yield information related to the optimal agent and dose for each participant; and (d) random assignment to one of four psychosocial/ pharmacologic treatment combinations, including community treatment control, medication without systematic psychosocial intervention, medication plus packaged psychosocial intervention, and medication plus tailored psychosocial treatment. Intervention will span two years, with careful monitoring of treatment integrity, with procedures to enhance continued participation of the subjects and their families, and with an outcome battery spanning multiple informants and domains of functioning. The overarching goal is to assess the combined efficacy of medication and intensive psychosocial treatments for altering the course of ADHD.